The invention relates to a compensating bearing, for example, a bridge bearing or a travel way bearing, in which a substructure and a superstructure are displaceably connected to each other by means of a sliding bearing, whereby the displacement occurs in a linear and/or cardanic manner in at least one of the directions X, Y, and Z in a hypothetical three-dimensional coordinate system.
Compensating bearings of this type, which for their part rest on abutments or piers, transfer the load from the superstructure to the substructure, whereby the superstructure moves in the longitudinal and/or transverse direction. In order to receive twisting angles, bearings of this type must, however, also be combined with a pivoting part.
A bridge bearing of this type according to the generic concept is known from the pamphlet xe2x80x9cInnovation in Steelxe2x80x9d, No. AG 01 D-3000-12.97 of the Maurer Sxc3x6hne Company. It consists of a base plate, on which an intermediate plate that can be moved in the X-direction is arranged, which in turn carries a second intermediate plate that can be moved in the Y direction. This second intermediate plate has a curved recess, in which a complementary spherical section is placed. This bridge bearing according to the generic concept is then closed by a cover plate, which can perform linear movements in the direction of the two axes X, and Y, and can pivot around the Z axis.
A bridge bearing of this type has, on the one hand, relatively large dimensions and on the other hand, is relatively imprecise in its adjustability with regard to the X, Y, and Z axes. An additional disadvantage is in its insufficient freedom of play.
The objective of the invention is thus to develop an improved compensating bearing while avoiding the previous disadvantages.
According to the invention, this objective is achieved by providing a carriage that is connected to a cover plate that is guided linearly in the X- and/or Y-direction respectively via two shafts that are set apart at distances from each other, on which slide bushings that can be moved are arranged and/or that the cover plate is guided so that it can be tilted in the Z-direction via a first pivot bearing.
The decisive advantage of this bearing is its clear differentiation with regard to the function of the three movement axes. The slide bushings ensure an absolute maintenance freedom at the lowest level of friction. Bearing elements that are adjusted to the load, such as slide bearings and pivot bearings, reduce the total weight of the bearing construction and require little construction space. The round and/or spherical bearing elements are self-centering, which makes possible a high precision and a good side stability. The combination according to the invention, made of linear bearings and plain bearings, enables all alignment errors arising as a result of finishing inaccuracies, foundation subsidence, desired and undesirable slanting to be compensated and regulates the variations in lengths due to temperature and load by having a good damping capacity.
An especially advantageous compensation bearing, which makes possible the reception of forces from all three movement directions, is also provided. This X-, Y-, and Z-bearing is characterized in that a base plate has four projecting shaft holders that are set apart from each other in the X-direction and in the Y-direction, and in which two Y-shafts are held, on each of the Y-shafts, an additional shaft holder is arranged so that it can be moved, which are connected to each other by two X-shafts, so that the carriage guided on the X and Y shafts via the sliding bushings can be moved linearly in both directions, and that the carriage has a curved shaft disc that is received in an associated recess of the cover plate so that the cover plate can be tilted in the Z-direction.
According to another characteristic of the invention, it is provided that the slide bushings are maintenance-free cylindrical slide bushings based on PTFE.
These dry slide bearings that are known to persons skilled in the art include cylindrical steel supporting structures and the maintenance-free slide layer. The steel structure protects against damages in the handling and during installation. The slide layer is generally formed of a 0.5 mm strong PTFE fabric, generally embedded in artificial resin and affixed in a high-strength manner to the support structure. The flow behavior of the slide layer is almost negligible in the connection with the support structure even for high loads. The adhesive connection is moisture-stable and does not swell.
In another aspect, it is apparent that the Y-shafts are affixed in the shaft holders using mounting caps, which are pressed from the outside against the shaft holder with a mounting bolt that is arranged in the facing ends of the Y-shafts. In this way, a simple and secure attachment of the Y-shafts results.
According to an additional characteristic of the invention, it is provided that the X-shafts each have a curved recess on the opposite ends, into which the Y-shafts are inserted with a part of their circumferential surface. This has the advantage that by the recess, the bearing attachment of the X-shafts is done in an elegant manner through the Y-shafts.
An especially advantageous form of the bearing according to the invention, provides that the base plate has in its middle part a supporting projection that projects in the direction of the cover plate and is contacted by the lower side of the carriage in the unloaded condition.
This has the advantage that the introduction of force on the bearing does not occur via the X- and the Y-shafts, but directly on the base plate, so that an entirely especially stable embodiment of the bearing results.
In another aspect, the X and/or Y shafts should have a deflection in the direction of the cover plate. This makes it so that shafts equipped in this manner have a certain spring action so that the bearing is pretensioned.
An additional, especially advantageous embodiment of the invention, provides that the carriage include in its middle part a hole going through that is provided with a shoulder. A second pivot bearing is set into the hole and is held via a mounting bolt that is inserted into the cover plate, whereby in the area of a journal of the carriage, a gap is formed between the mounting bolt and the through-hole. In this process it is advantageous that upon a change of the forces into the negative range, the Z-axis can not lift off of the cover plate, i.e. a securing against lift-off is formed. In this case, it is necessary that both pivot bearings have a common spherical center.
In another aspect, the pivot bearings can be constructed as maintenance-free axial plain bearings, radial plain bearings, or inclined plain bearings based on PTFE. These pivot bearings are pre-assembled units, which include shaft discs and housing discs and maintenance-free slide layers in the housing discs. The shaft disc has a spherical outer sliding path, while the housing disc is provided with a hollow-spherical inner sliding path and with an adhered slide layer. Pivot bearings of this type are then used if, for example, high loads are transferred with slight movements.
An additional advantageous embodiment form of an X-Z-bearing is described, in which a base plate has two projecting shaft holders that are set apart from each other in the X-direction in which two X-shafts set apart from each other are held. Slide bushings that can be moved in a linear direction that are connected with the carriage are arranged on the X-shafts, and the carriage has a curved shaft disc that is received in a corresponding recess of the cover plate so that it can be tilted in the Z-direction.
The associated opposing piece, namely a Y- Z-bearing, is also provided in which a base plate should have two projecting shaft holders that are set apart from each other in the Y-direction in which two Y-shafts that are set apart from each other are held, on which slide bushings are arranged on the two Y-shafts that can be moved in a linear direction and are connected with the carriage, and the carriage, has a curved shaft disc that is received in a corresponding recess of the cover plate so that it can be tilted in the Z-direction.
Finally, a Z-bearing is described, i.e. a bearing with only one degree of freedom. Bearings of this type are used especially as so-called fixed bearings. It is characterized in that the base plate is provided with a projection that projects in the direction of the cover plate, which is provided on its upper end with a circular-ring shaped curved shaft disc, which is included in a corresponding recess of the cover plate so that it can be tilted in the Z-direction.
BRIEF DESCRIPTION OF THE DRAWING(S)
The invention is explained in greater detail on the basis of the preferred embodiment in connection with the attached drawings.
Shown are:
FIG. 1 is a perspective view of an X-, Y-, and Z-bearing according to the invention,
FIG. 2 is a front view of this bearing,
FIG. 3 is a side view of this bearing, in partial section,
FIG. 4 is a section view along the line Axe2x80x94A in FIG. 3,
FIG. 5 is a section view along line Bxe2x80x94B in FIG. 3,
FIG. 6 is a perspective view of an X-, Z-bearing according to the invention,
FIG. 7 is a perspective view of a Y-, Z-bearing according to the invention,
FIG. 8 is a perspective view of a Z-bearing according to the invention,
FIG. 9 is a side view of the bearing according to FIG. 8,
FIG. 10 is a section along the line Axe2x80x94A in FIG. 9,
FIGS. 11-15 are sequential perspective views of an X-, Y-, Z-bearing according to the invention during different stages of construction.
FIG. 16 is a side view similar to FIG. 3, in which the X-shafts have a deflection in the direction of the cover plate.